When the mood strikes, few bands do bong-rips-in-your-Dodge-Dart badass quite like Pittsburgh's Zombi. The sound Steve Moore and Anthony Paterra make-- equal parts Italo-funkers Goblin, Can's lockstep whirl, intro music to educational filmstrips of the 1970s, and Edgar Winter's undead "Frankenstein"-- can be almost impossibly epic. When it works, as it did over and over again on 2006's Surface to Air, it feels like a vision quest through the bowels of hell. But whereas Surface found myriad ways to match looming dread with body-rocking thunder (they are on Relapse, after all), Spirit Animal plays the extremes. The heights can be towering, the lows crushing, but the relative lack of middle ground keeps Spirit Animal off balance and a few shades shy of truly badass.

Instrumental rock of this sort requires a certain ratio of tension and release; the tunes range in length from a lean six minutes and change to the comfortably numbing 17-plus minutes of closer "Through Time", and too much time spent at either end of the spectrum can be stultifying when you get into the lengthier numbers. Often Spirit Animal gets so caught up in its own grooves it almost seems to forget there's anybody listening; where a constant dynamism bubbled under the comparably hefty Surface to Air, Spirit Anim**al too often finds Zombi settling into one mode or the other-- spacey, or spooky, but mostly skull-smashing-- and letting it ride just a touch too long. Individual moments can crush or creep, but far too many riffs get turned every which way but out, and far too few of those are quite badass enough to justify the time they spend with 'em.

Spirit Animal is almost certainly the band's loudest effort; half-Zombi Steve Moore even sneaks a little electric guitar in there, a first for the band on wax. If you'd told me either of those things before I heard the record, I would've pegged it as their best based on that alone; it's not that Zombi really needed to get louder or introduce new elements into the mix, but that'd certainly be a direction you'd think they'd revel in. They do, but as a listener, it's hard not to feel bludgeoned by the oft-endless riffage that characterizes much of Spirit Animal. Given their relatively small arsenal of instruments and an apparent unwillingness to shed the ghosts of their influences, I suppose there's only so many things they can do without going way way out, and Spirit Animal finds them doing just that. But unlike Surface to Air-- or even the terrific "Infinity" from their recent split with Maserati-- the sprawl becomes a crawl, and the rift between the parts that kick your butt and the parts that get you primed for said butt kicking is just a bit too great for Spirit Animal to achieve the kind of balance Zombi have been so adept at in the past. In the end, Spirit Animal becomes less like the badass elephant on its front and more like just another pachyderm; heavy, yes, but lumbering.